backends/baum.c: Fix compilation when SDL is not available.

backends/baum.c: In function ‘chr_baum_init’:
backends/baum.c:569:64: error: missing binary operator before token "("
 #if defined(CONFIG_SDL) && SDL_COMPILEDVERSION < SDL_VERSIONNUM(2, 0, 0)
                                                                ^
backends/baum.c:598:64: error: missing binary operator before token "("
 #if defined(CONFIG_SDL) && SDL_COMPILEDVERSION < SDL_VERSIONNUM(2, 0, 0)

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 1395437377-5779-1-git-send-email-rjones@redhat.com
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>